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Dunhuang

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Dunhuang (LANDNET SITE)

This site was operational radiometric calibration and validation for Chinese satellite sensors in 2001, and located on the east edge of the Kumutage Penniform Desert in Gansu province, South-West China. It is a Gobi desert, and about 35 km west
the city of Dunhuang . The whole target area for vicarious calibration is situated on a stabilised alluvial fan, 30 km x 30 km size. The area used for high spatial sensors (such as CBERS, TM etal) vicarious calibration measurements is approximately 400 m x 400 m in the centre of the fan and the surface comprises cemented gravels, and 15km×15km for low spatial sensors (Such as NOAA/AVHRR, FY-1/FY-3 optical imagers and EOS/MODIS etal )vicarious calibration with no vegetation. Sources of meteorological data for the site include the Dunhuang-PAM automated weather station, which is part of the Asian Automatic Weather Station Network. Atmospheric aerosols over the site are typical of a rural continental location, although some larger particles were observed, possibly influx from the sand dunes to the north-west. Sandstorms affect the site on around 8 days per annum and atmospheric dust is a significant factor on around 60 days per annum. [1]

It is one of the CEOS LANDNET Sites. The site is managed by NSMC/CMA; for more detailed information regarding the site, the point of contact is Xiuqing Hu (huxq@cma.gov.cn)

Instruments on the Test Site

  • ASD field spectroradimeter (350-2500nm)
  • Sunphotometer (CE318)
  • Weather observation (Dunhuang weather station)
  • Ground surface and Soil Temperature

 

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Climatological Data for Dunhuang

Parameter Mean Std Dev Min Max Max-Min (Max-Min)/Mean CV
Cloud Fraction (%) 0.4080 0.1247 0.1830 0.5964 0.4134 1.0132 0.3055
Water Vapour Content (g/cm2) 0.8692 0.6696 0.2490 2.1530 1.9040 2.1906 0.7704
Precipitation (mm/day)  0.1836  0.1988  0.0075  0.6511 0.6436 3.5059 1.0827
Ozone Content (Dobson) 316.7750 24.2629 289.0000 349.1000 60.1000 0.1897 0.0766

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Temporal Variability of Cloud Fraction: on the X axis scale is one year (Jan-Dec); on the Y axis scale is the fraction 0-1
Temporal Variability of Water Vapour Content: X axis scale is one year (Jan-Dec); Y axis scale is 0-6 g/cm2
Temporal Variability of Precipitation. X axis scale is one year (Jan-Dec); Y axis scale is 0-10 mm/day
Temporal Variability of Ozone Content. X axis is one year (Jan-Dec); Y axis is 0-500 Dobson
Spectral Temporal Variability  

 

Literature

 

Links

 

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 References

[1] NCAVEO - Dunhuang Page

[2] WP230 - Site Characterization from Climatological Dataset

[3] QA4EO Document - QA4EO-WGCV-IVO-CSP-002 - PDF

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